This invention pertains to a heat pump system and more particularly, to an improved heat pump system incorporating combination variable orifice metering and check valves.
A basic air conditioning system comprises a compressor, an outdoor coil, expansion means and an indoor coil. High pressure vaporous refrigerant from the compressor is condensed in the condenser, which is air cooled or water cooled, as is well-known in the art. The liquid refrigerant is metered through the expansion means, which is conventionally a thermal expansion valve or a capillary tube. As the refrigerant expands and returns to the vaporous state in the indoor coil, it cools the indoor coil and air passed over the indoor coil from the area to be treated or conditioned, for example, a room in a house, is cooled.
Such basic air conditioning system can be adapted to a heat pump system to selectively heat or cool the area to be treated by adding a four-way reversing valve in the refrigerant circuit between the compressor and the indoor and outdoor coil. The heat pump system will function as a basic air conditioning system to cool the area to be treated when refrigerant is ported first to the outdoor coil. If refrigerant is ported first to the indoor coil, the air passing over the indoor coil will be heated and heated air will be supplied to the area to be treated.
A typical heat pump system is shown in Hale U.S. Pat. No. 3,170,304. Such system includes expansion means comprised of a thermal expansion valve for each mode of operation and a separate check valve disposed in parallel circuit flow relationship with each thermal expansion valve. For cooling, the check valve adjacent the outdoor coil is open and the check valve adjacent the indoor coil is closed. The thermal expansion valve adjacent the indoor coil will control the flow of refrigerant to the indoor coil. For heating, the check valve adajcent the outdoor coil is closed and the check valve adjacent the indoor coil is open. The thermal expansion valve adjacent the outdoor coil will control the flow of refrigerant to the outdoor coil. The respective thermal expansion valves can be designed for the same size flow rate or different size flow rates to accommodate specific system applications.
The present invention provides a combination variable orifice metering and check valve that is intended to be substituted for a separate thermal expansion valve and separate check valve. The novel combination valve provides a variable control of refrigerant flow in a more simple, economical and less expensive fashion than does a conventional check valve in parallel flow relationship with the thermal expansion valve.
The prior art does disclose some valves having superficial similarity to the combination variable orifice metering and check valve of the present invention, but they are intended for purposes other than heat pump systems, hence they are constructed differently and function differently from the novel combination valve of the present invention. For example, Sands U.S. Pat. No. 2,623,725 shows a safety valve for controlling flow in one direction and shutting off flow in the opposite direction. Francher U.S. Pat. No. 3,067,770 pertains to a valve of the charge and spill type. Sands U.S. Pat. No. 3,122,162 pertains to a flow control device that represents an improvement over the subject matter of the Sand U.S. Pat. No. 2,623,725. Hansen U.S. Pat. No. 3,580,274 shows a combined pressurizing and relief valve in the control head of a fire extinguisher. None of these prior patents suggests the novel combination variable orifice metering and check valve means for a heat pump system disclosed herein.
An object of the present invention is to provide an improved heat pump system incorporating combination variable orifice metering and check valve means wherein the disadvantages and deficiencies in prior heat pump systems are overcome.
Another object of this invention is to provide a novel combination variable orifice metering and check valve for a heat pump system. Other objects and advantages of the present invention will be made more apparent in the detailed description of the invention which follows.